hero419

I bought a rear rack yesterday and it did not fit my cypress.
is also did not fit my wife's Haro.
My bike does not have any mounting holes around the seat stays so I tried to use the brake mounts or the seat post clamp. It would have worked if the brackets were long enough. So I am going to take it back and look for another one.

Does anybody have pro's con's on the seat post mounted racks? I know they only hold 20lbs.
Are they stable?

I also bought an Axiom bag. That thing is awesome! Great size and features, it even has side "pouches that unzip and turn into mini panniers.

any advise would be apreacatied

tsl

I dunno. They always make me think of a diving board...

I have a Jandd Expedition rack on my Cypress DX. The upper mounts are long enough to fit in the seatpost clamp, the whole rack sits rearward enough that heel-strike isn't a problem (an issue I'd had with other racks on this bike) and my taillight tucked in nice and protected underneath the deck by reversing the included reflector bracket.

Steve Hamlin

I've got a Cypress, too. . .

Seat-post mounted racks not only don't support a lot of weight, but they shift your center of gravity up instead of down -- to the seatpost instead of rear hub level.

You can use the rack you got, but you'll need a gadget like this:

https://www.bikeparts.com/search_resu...p?ID=BPC306017

I cobbled together one for my bike because at the time this gadget ran to about $18 which I thought a bit steep for pieces that any hardware store carries. . .

While you could probably come up with a way to attach the top of the rack to the brakes or the seat post, I always veer towards the "what's the worst that could happen?" theory. Probably nothing ever for you, but for me it would be failure of the attachment while high-balling down a cliff-sided mountain road with full panniers.

hero419

Well I went for the seat post mounted "diving board". I picked it up yesterday and mounted it.
Things I like:
-easy mount/dismount
-works with same brand "rail" system, where bags just snap on and off

Things I dislike:
-expensive - 50 bucks!
-holds on 20lbs (but then again I'll never have that much(I think))

It seams very stable. the place where it mounts has no effect on the center of gravity....
It is the location of the mass that effects it. this thing could mount to the front of the bike, rap around to the back and be located over the tire and still have the same center of gravity.

Also I had my first bad experience with the LBS..
there was a teenage kid working. He told me that he could mount that rack on many bikes including mine (as if I am an idiot with no experience with mechanics (nice assumption butt head)) and then proceeds to the closest Giant cypress and finds out he is wrong. so then I am thinking about getting something along the same design as the previous one with the exception of longer brackets. But he says that the post mount is the only way to go.

Well me being a quite pacifist and having a short time line, I say OK

I am not going to let this kid ruin my expectations of LBS's but I will most likely be going to the other ones in the area.

I would post pics but the file size is always to big...

ItsJustMe

Seat post racks are pretty useless.
Here's a pic of my Cypress with a rack on it. I used the seat post bolt. I didn't find any racks that wouldn't fit like that; you must have "lucked out".
https://www.hauntedfrog.com/gallery2/...geViewsIndex=1

ItsJustMe

Do physics much? This statement is false. The center of gravity is the center of mass. If there is 20 pounds of stuff sitting on the rack, and the seat post rack and the normal rack are at the same position, the center of gravity of the bike is exactly the same either way. It's a rigid body with masses distributed around it. It doesn't matter how they're hooked together.

Besides, on a bike you want a HIGH center of gravity. Why? Put a 1 pound weight on a 1 foot stick, then try to balance it on your hand. Now put it at the end of a 6 foot stick and try. The high CG is much easier to balance.

hero419

[quote=ItsJustMe;5391297]Do physics much? This statement is false. The center of gravity is the center of mass. If there is 20 pounds of stuff sitting on the rack, and the seat post rack and the normal rack are at the same position, the center of gravity of the bike is exactly the same either way. It's a rigid body with masses distributed around it. It doesn't matter how they're hooked together.[QUOTE]

+1

"It seams very stable. the place where it mounts has no effect on the center of gravity....
It is the location of the mass that effects it. this thing could mount to the front of the bike, rap around to the back and be located over the tire and still have the same center of gravity."

This is what I stated earlier

Aslo, why do you think a seatpost mounted rack is useless?

by the way, I do not have the bolts (on the seat poste) on my model like you have
must be a diffrent year

Steve Hamlin

I think iif I put a brick on a beam-type seat post mounted rack, the center of gravity will be pretty much the center of the brick.

If I put it on a full blown rack, the center will be shifted because the "triangular" rack and the mass of the brick are in essence a single unit. . . the load path, blah, blah, blah. . .

cq: https://www.grc.nasa.gov/WWW/K-12/airplane/cg.html

All rather begging the question of why I would have want to carry a brick. . .

To return to the original thread, I got a seat post rack for my wife's Cypress -- for light loads, it's just fine.

I have to agree, the geometry and or tube diameters must've changed year to year. . .

discosaurus

Mounting a rack on my Cypress just took a couple extra brackets.